Guava it’s Diseases and their Management

Guava it’s Diseases and their Management

Guava (Psidium guajava L.) is an important fruit of subtropical countries. It is hardy crop and is cultivated successfully even in neglected soils. It is a small or shrub like evergreen tree. It has slander like trunk with smooth red green bark. Oval shape fruit green to yellow in color. Its   height is about 33ft and life span is approximately 40years. Pakistan is second largest guava producing country. According to (PCRSC) survey of Pakistan (2015-16) 70026 hectare area under guava cultivation and its production is 414649 tons annually. Some major and impressive guava benefits on human health are; it manage blood pressure, help in digestion, weight loss, improve immunity system, healthy eyes, prevent from cancer. There are number of pathogens, mainly fungi, which affect the guava crop besides few bacterial, algal and some physiological disorder.  About 177 pathogens of which 167 are fungal 3 bacterial, 3 Algal, 3 Nematode and 1 apiphyte. These pathogen causes different type of diseases in guava plant at different stages from growing stage to maturity and fruiting time. Postharvest and fruit diseases are also important which cause serious losses. Fruit disease have also two types i.e.; field disease and postharvest, which develop during storage and transit. In the present communication some major diseases are describe with their symptom and disease management practices.

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Diseases Symptoms, survival and spread, Favourable condition and their management:

Guava Wilt:

Diseases Symptoms:

Muhammad Abdul Rehman

Department of Horticulture, College of Agriculture, University of Sargodha

  • In this diseases pathogen mostly attack young as well as old fruit bearing trees
  • Symptoms mostly start with the on fall of monsoon appearance of light foliage with the loss of epinesty & turgity
  • Roots of the plant also show rooting at the basel region
  • Bark of the plant can be easily detachable from the cortex
  • Light browned blotch can also be observed in vascular tissue

 Favourable Conditions:

  • Highly rainfall during Aug-Sep
  • For long duration stagnation of water in guava field
  • RH 76% are conducive with min to max temperature range (23-32°c)

Spread & Survival:

  • Mostly spread by water in short distance
  • Wild disease can also be predisposes through root injury

Management:

  • We can manage the disease through proper sanitation.
  • Through solarization of the soil.
  • Burnt wilted plants and uprooted.
  • Treat guava plant with 0.1% water soluble 8 quinolinol sulphate .it may provide protection to the plant for at least 1 year against wilt.
  • Harsh pruning followed by a drench with 0.2% Bavistine or Benlate 4time in a year.

Fruit Rot:

Disease Symptoms:

  • In this disease mostly start of calyx disease of fruit during raining season
  •  The fruit near soil level coverall with dense foliage are mostly effected under high relative humidity
  • With cotton like growth covered the inffected area which develops very fast as fruit matures. Pathogen can be able to cover the entire surface during the humid weather within a period of 3-4 days
  • Fruit skin below the whitish cottony growth become a little soft, turn light brown to dark.

Favourable condition:

  • Poorly drained soil and injured, high humidity, temperature from (28-32°c) favourable for the iniation of disease
  • High soil moisture, cool, wet enviormental condition favourable  to disease development

Spread and Survival:

  • Greet no of sporangia and spores can be produce on the surface of diseased tissues principally by pathogen when temperature  near to 25°c
  • Spores can also be spread through infected plant material or soil by rain splashes

Management:

  • Kothari (1968) recommended weekly spray of Bordeaux mixture and copper oxychloride.
  • Management of dry rot through the use of fungicides like Ziride 0.3%.
  • Seed treatment with Bavistin 3g/kg seed controls the disease effectly.

Fruit canker:

Disease symptoms:

  • The symptoms of this disease occur generally on green fruit and rarely on leave
  • Effected fruit remain under develop, become hard, mummified malformed and drop. Sometime, small rusty brown angular spots appear on the leaves
  • Crater like appearance is more observed on fruit then leaves
  • Margin of lesion is elevated and a depressed area is observed in inside
  • On start minute, circular, unbroken brown necrotic area appear in fruit advance  stage of infection, Tears open the epidermis in a criminate manner

Favourable conditions:

  • Spores germination will be maximize at 30°c and can’t germinate below 15°c or above 40 with RH above 96%

Spread and survival:

  • The pathogen is primary a wound parasite and avoid injury to fruits

Management:

  • Spread disease can be controlled by 3 or 4 spray of 1%of Bordeaux mixture or lime sulphate at 15days interval.
  • Naisk and cultives Sind show good resistance against this disease.
  • Safeda and apple color verities are highly resistant against this disease.
  • The homoeopathic drugs, potassium iodide and arsenic oxide completely inhibited spore germination.it can also inhibit the growth of pathogen.

Algal Leaf & fruits spots:

Diseases Symptoms:

  • In this disease immature guava leaves infect during early spring fall
  • On the leaves minute, shallow brown lesion appear especially on the tip of leaf, areas or margins adjacent the mid vein and as the disease advance, lesion in large in diameter from 2-3mm
  • The spot on the leave may vary from specks to big patches which may be scattered or crowded
  • The lesion on immature fruit are nearly black, lesion get sunken & cracked frequently as fruit enlarge
  • Lesion are smaller than leaf spot. They convert their color from darkish green to black

Favourable conditions:

  • By splashing water zoospore spread
  • Disease can also spread through humid wet condition

Spread and survival:

  • Air borne diseases mostly spread through air or rain splashes
  • On the infected plant debris pathogen survive

Management:

  • High sanitation required because algae can survive on fallen leaves during winter.
  • Discard of infected debris carefully to prevent spread of disease.
  • Prune plants to improve air circulation and excess of sunlight.
  • Avoid wetting of leaves as much give water at the base of the plant.
  • Apply Bordeaux mixture or copper based fungicides if plant seriously infected.

Stem canker & Dry fruit rot:

Diseases Symptoms:

  • In this disease pathogen mostly attack on main branches & stem on which it causes cracking of lesions
  • In perfect stage diplodia netalensis dry fruit rot, Physalopara psidii causes stem canker
  • On the infected stem through fungal perithesia small brown to black structure may develop
  • Symptoms appear on the fruits as light brown spots generally at the stalk or calyx end
  • The entire fruit becomes dark brown to black & mummified with 4 days
  • Twing bearing infected fruits show dieback

Favourable Conditions:

  • For disease development rainy season is favourable
  • Humidity & wet condition required

Spread & Survival:

  • Pathogen spread through air from plant to plant
  • Patgogen survives beneath the bark of the plant & become active when condition are Favourable

Management:

  • High sanitation required.
  • Management of dry rot through the use of fungicides like Ziride
  • Mostly recommended spray of Bordeaux mixture and copper oxychloride

Dieback and Anthracnose (Fruit rot)

Disease symptoms:

  • Fruit and leaf infection phase: During rainy season infection can be seen on unripe fruits pinhead spot are first seen which gradually enlarge.
  • In dark brown color spots sunken, circular and have minute black stromata in the center of lesion, in moist weather produce creamy sporemasses.
  • To form bigger lesion several spots coalesie.
  • Infected area of unripe fruits become corky and in case of severe infection often develops cracks.
  • Bud and flowers which are unopened are also effected and cause their shedding.
  • The fungus cause necrotic lesion usually ashy gray and bear fruiting bodies at the tip or on the margin of the leaves.
  • Die back phase: From the top of a branch; plant being to die backwards touxy shoots, leaves and fruits are readily attached. The greenish color of young growing tip change into dark brown and later to black necrotic areas extending backwards.

Favourable conditions:

  • Rain splashes, wind encourage the spore production and its dispersal around the canopy.
  • Without canopy management closer planting
  • Temperature between (10-35°c) with best of (24-28°c).

Spread and survival:

  • Through infected foliage moment of plant material.
  • By wind borne spores develop on dead leaves, twigs and mummified in the orchard infection spreads.
  • Transportation of fruits through high disease prone area.

Management:

  • Apply streptosporangium pseudovulgare before appearing symptoms.
  • Spray copper oxychloride 50%WP @ 4gm/lit.

To conclude the above mentioned are some major diseases of guava. Guava is an important fruit crop of Pakistan and grown on large scale. It is an economic fruit that provides good income to the growers. It is a nutrient-dense super food and provides much health benefits to humans. But due to attack of diseases on this nutritious fruit crop as well as due to lack of knowledge among farmers about disease management annual losses are quiet high. So, we should have to give proper care to guava crop regarding disease management if we want to take benefits from this in future.

Salient Features of Guava Cultivation

Hamza Javaid, Mujahid Ali, Dr. Rashad Mukhtar Balal

(Horticulture, College of Agriculture, UOS)

 On this planet of earth, fruits are one of those blessings that do not have any substitute. There are many species of fruits known today and every single fruit is beneficial for our health with its exceptional nutrients, require for our growth and development. Every fruit has a Devine taste that makes our taste bud satisfied. Our main fruits are apple, date palm, guava, kinnow, mango, peach etc. Guava is our 4th most important fruit crop. It is famous for its vitamin C. It is said that “Guava is the king of vitamin C, as its 100g of fruit contains 280 mg vitamin C.”

Botanical name of guava is Psidium guajava L. and it belongs to family Myrtaceae. It is called “poor man’s fruit” or “apple of tropics” and is a popular fruit tree of the tropical and subtropical climate and is native to tropical America stretching from Mexico to Peru. Guavas are cultivated throughout the tropical and subtropical areas of Africa, South Asia, and South East Asia. Top guava producing countries are India, China, Thailand, Pakistan, Indonesia, Brazil, Bangladesh, Philippines, and Nigeria. In Pakistan, it is grown in all the provinces over an area of 144556 hectares with the production of 468.3 thousand tonnes. The major guava growing areas include Shariqpur, Kasur, Lahore, Sheikhupora, Sangla Hills, Gujranwala in Punjab; Kohat, Haripur, and Bannu in the North West Frontier Province and Larkana and Hyderabad in Sindh. Guava fruits are used both, as fresh consumption and processing. It excels most other fruit trees in adaptability, productivity, hardiness and most importantly in vitamin C. Besides its high nutritive value, it bears heavy crop every year and gives good economic returns involving very little input. Guava is the one of the most gregarious of fruit trees of the myrtle family (Myrtaceae) and is almost universally known by its common English name or its equivalent in other languages. The Dutch call it guyaba, goeajaaba, the Surinamese, guave or goejaba, and the Portuguese, goiaba or goaiberi, in Spanish, the tree is guayabo, or guayavo, the Surinamese, guave or goejaba, the Portuguese, goiaba or goaiberi, for Hawaiians it is guava or kuawa. In Malaya, it is generally known either as guava or jambu batu. Various tribal names pichi, posh, enandi, etc. are employed among the Indians of Mexico and Central and South America. In Pakistan, it is locally known as amrood.

Guava is partly deciduous, shallow-rooted shrubs or small tree that grows 4 to 5m in height but in exceptional cases, it may attain a height of 9 m, with spreading branches. Leaves are light green in color 7 to 15 cm in length. The flower is white in color, complete and sometimes grow singly and sometimes it grows in clusters. Plant stem skin brown in color, smooth and scaly, flower bud mixed. It has an edible round or pear-shaped sweet fruits usually 5-10 cm in diameter. The fruit has a thin peel, usually red, pale green or yellow when mature. The flesh of some varieties is hard (crunchy like an apple) other cultivars are white or pinkish in flesh color and soft when ripe with a strong, very characteristic fragrant scent. The fruit center core contains many small hard seeds.

Guava can grow in both humid and dry tropical or subtropical regions of the world and it is cold sensitive. Minimum required temperature is 20 degree Celsius and the optimum required temperature is 23 to 28 degree Celsius. Guava cannot tolerate a high temperature of desert regions. Guavas cannot tolerate frost. Guava is cultivated on varied types of soils- heavy clay to very light sandy soils. Good quality guavas are produced in river-basins. It tolerates a soil pH of 4.5- 8.2. The maximum concentration of its feeding roots is available up to 25 cm of soil. Good drainage is recommended but guavas are seen growing spontaneously on land with a high water table, too wet for most other fruit trees. Besides all these, guava is a bit salt resistant as well.

Propagation is done in both ways sexually (through seeds) and asexually (through cutting, budding, grafting etc. In Sexual Propagation, seeds are separated from healthy fruit and are sown to raise seedling and then transplanted to the actual field. The propagation of guava through seeds should not be encouraged because the seedlings have long juvenile phase, give lower yields and bear poor quality fruits. But the seedlings serve as rootstock material for grafting or budding. The seeds should be sown as soon as possible after extraction from the ripe fruits. Soaking of seeds in water for 12 hours or in hydrochloric acid for 3 minutes gives about 90% germination. About 1-year-old seedlings become ready for grafting or budding. For planting seedlings, seed should be collected from the plants producing high-quality fruits and high yield. Asexual Propagation is done through inarching, budding, grafting and somewhere through layering as well. In Pakistan, layering is done only in Haiderabad as it has high success rate there. Healthy, diseased free softwood stem cuttings and bud sticks are used. Seedlings are raised for budding and grafting. Varieties of guava contain Allahabad, Chinidar, Karela, Seedless, Hifzi, Safeada etc.

The filed for planting is prepared during the summer season by plowing, leveling and removing weeds. The pits of 1m x1m x 1m size are dug and filled with a mixture of farmyard manure and soil. If the soil is good and irrigation facilities are available, the preparation of land and digging of pits are not required. The planting is done during the rainy season by adopting square planting system. Guava is commercially planted at a distance of 5-8 m. The exact planting distance is, however, decided according to variety, soil fertility and availability of irrigation facilities, for example, guava Lucknow 49 needs more spacing than apple guava and Allahabad Safeda. Under irrigation and high soil fertility, the plants become very vigorous requiring more spacing. In normal conditions, a planting distance of 7 m is optimum. High-density planting reduces total soluble solids, sugars, and ascorbic acid but increases irritable acidity. The lower plant population results in the spread of crown, while higher planting density causes the erect growth of branches making the plant tall and compact. High-density planting gives higher yield/ unit area in early years of fruiting.

Traditionally, no pruning is done in guava because the plant bears heavily even without it. But no pruning results in the formation of narrow crotches, limb breakage due to heavy fruit load and overcrowding. Therefore, training of plants in the young stage to build the strong framework and to avoid weak crotches is necessary, whereas fruiting trees should be trained as low headed trees to facilitate multiple hand pickings. The scaffold branches in young plants are to be tipped back to encourage secondary branching of the root sucker, water sprouts and crisscross branches are to be removed altogether. In every growing season, a large number of new shoots emerge on a guava tree and majority of these are lateral. Very few are terminal. These shoots produce fruits. After 1 year most of the lateral shoots dry out, while terminal shoots put forth the extension growth. Hence, to check the overcrowding and to control the plant height, the terminal shoots on the periphery may be headed back at about 40 cm level in alternate years. Pruning also takes place during harvesting as the fruit is plucked along with the shoot on which it is borne. Pruning is usually recommended after harvesting or in spring. Summer pruning may damage the plant by sun burning.

Although guava is grown without the application of any manure and fertilizers it responds very well to its application by giving higher yield and better quality fruits. Fertilizers should be applied one foot away from the stem. Fertilizers should be applied after harvesting and before fruit setting in winter and the fertilizers application should be based on leaf nutrient status off an orchard. At the age of one year; 20kg FYM, 125g urea is recommended. For 2 years old plant; 20kg FYM, 250g urea, and 250g DAP is recommended. For 3 years old plant; 20kg FYM, 500g urea, and 500g DAP is required. At the age of 4 years; 40kg FYM, 750g urea and 750g DAP is recommended. For 5 years old and above plants; 50kg FYM, 1kg urea, and 1kg DAP. Guava does not require much care after planting. The weeds are removed by shallow cultivation. Green manuring should be done during the rainy season and clean cultivation during rest of the year. Leguminous crops can be grown as an intercrop during first three years of planting to obtain more income and to increase N content in the soil.

Guava is mostly grown under rainfed conditions and irrigation is rarely practiced wherever this facility is available. However, irrigation enhances the yield of guava by making the plant more vigorous and increasing the fruit set. Irrigation is especially desirable after planting for the survival of the plants and thereafter for 2-3 year to obtain early good growth. Irrigation of fruiting plants depends upon the adoption of a particular cropping pattern. For the whole year, cropping pattern which is commercially adopted all over the country except the northern region, irrigation is essential during the summer season. Irrigation is given to make the soil of root zone moist, thus heavy irrigation is unnecessary. The fruit quality of guava is adversely affected by high soil moisture content during harvesting. The young plant needs careful irrigation. Plants need more water when they have fruit on them. Lower the water supply at the time of flowering. In summer, irrigation should be done with the interval of 10 days. In winter, irrigation should be done with the interval of 25 days.

Guavas are harvested throughout the year (except during May and June). However, peak harvesting periods are August for rainy season crop, November-December for winter season crop and March- April for spring season crop. The fruit matures 90 to 150 days after flowering. Guava fruits develop best flavor and aroma only when they ripen on tree. In most of the commercial varieties, the stage of fruit ripeness is indicated by the color development which is usually yellow. For local market, fully yellow but firm fruits are harvested, whereas half yellow should be picked for distant markets. The fruits are harvested selectively by hand along with the stalk and leaves. The plants begin bearing at an early age of 2-3 years but they attain full bearing capacity at the age of 8-10 years. The yield of a plant depends on its age, cropping pattern and the cultural practices. A 10 year-old plant yields about 100kg of fruits every year. Because of their perishable nature, guava as disposed of immediately after harvesting in the local market and a very small quantity is sent to distant markets. Since fruits are sold at a cheaper price and are available for a very long period of the year, they are not kept in cold storage. However, shelf life of guava can be extended up to 20 days by keeping them at low temperature of 5oC and 75-85% relative humidity. It can also be stored for about 10 days at room temperature (18`-23°C) in polybags providing a ventilation of 0.25 %. By following these practices, we can enhance our guava production.

Guava plants are attacked by wilt, which alone causes heavy losses. It is very difficult to find out an orchard of guava more than 30 years of age because most of its plants die at about 20 years of age due to wilt. Various fungi causing wilt are Fusarium roseum oxysporum, F. psiddi, F. solani, Macrophomina phaseolina and Gliocladium roseum. The resistant rootstock is the only solution. The planting material should not be obtained from a wilt infected region or nursery.

The fruit fly is the major challenge to summer season crop. The insect lays 150-200 eggs at a tie inside the fruit inserting ovipositor at maturity stage. Eggs hatch within 2-3 days and start feeding on fruit pulp. To check the attack of the fruit fly, traps of Methyl eugenol are used.